Absorbent article and method and device for manufacturing absorbent article
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Solution Overview
Problem
Conventional methods for manufacturing absorbent articles, such as disposable diapers, face challenges in maintaining stretchability in regions inward of side-seal sections due to contraction of elastic members, leading to unsuitable product quality.
Innovation Solution
A method and device for manufacturing absorbent articles that involve arranging elastic members between facing surfaces of sheet-like members, forming joining portions to sandwich and press the elastic members, and overlaying a second sheet-like member, ensuring that at least one joining portion overlaps with the side-seal section to prevent contraction-induced loss of stretchability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If elastic members are attached without adhesive, then softness and elasticity are improved, but attachment reliability deteriorates
Solution Approach 1:
The patent introduces joining portions as intermediary elements that mediate between the elastic members and the sheet-like members. These joining portions are formed by welding the sheet-like members to each other, creating a reliable attachment mechanism without using adhesive that would harden and reduce softness. The joining portions act as a mediator that provides both mechanical attachment and maintains the desired softness of the final product.
Solution Approach 2:
The patent replaces the chemical bonding mechanism (adhesive) with a mechanical bonding mechanism (welding). By welding the sheet-like members to form joining portions that sandwich the elastic members, the system achieves reliable attachment through mechanical interlocking and friction, eliminating the need for adhesive while maintaining both attachment reliability and softness.
2Reliability
If elastic members are stretched during manufacturing, then attachment effectiveness is improved, but contraction after cutting causes harmful effects
Solution Approach 1:
The patent applies preliminary action by forming the joining portions while the elastic members are in a stretched state, before the cutting operation occurs. The sheet-like members are welded to each other at positions that sandwich the stretched elastic members, creating attachment points that are established when the elastic members are extended. This preliminary attachment ensures that when the elastic members contract after cutting, they remain securely held by the joining portions, preventing harmful distortion and detachment.
3Reliability
If joining portions are formed on both sides of elastic members, then attachment reliability is improved, but risk of entering inward region increases
Solution Approach 1:
The patent applies local quality by making the joining portions overlap with the side-seal sections, creating a localized zone where the attachment function is enhanced. The side-seal sections serve as a boundary marker, and the joining portions are positioned to extend into this zone, ensuring that the elastic members are securely attached without extending too far into the inward region. This localized overlap provides both reliable attachment and precise positioning control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively suppresses the formation of non-stretchable regions within the absorbent articles, ensuring consistent stretchability and product quality by securely attaching elastic members between joining portions and side-seal sections.
Implementation Method 1
the elastic members 35' that have been cut contract in the direction of transport and attempt to expand in the CD direction
Implementation Method 2
the elastic members 35' are substantially sandwiched and pressed in the CD direction by the joining portions j
Implementation Method 3
the first sheet-like member and the second sheet-like member being overlaid in a thickness direction and welded together in the side-seal section
Data Source
Figure 1A
Figure 1B~1C
Figure 2
AI summary
A method for manufacturing an absorbent article, includes: an arranging step of arranging elastic-member continuous bodies (35a) between a pair of mutually-opposing facing surfaces of a first-sheet-like-member continuous body that is continuous in the direction of transport, the elastic-member continuous bodies being stretched; a joining-portion forming step of forming joining portions (j) that joins the pair of facing surfaces to each other; a step of overlaying a second-sheet-like-member continuous body on the first-sheet-like-member continuous body and subsequently forming the side-seal section (SS) on each of two sides of each of cutting target positions (PC) in the direction of transport, these sheet-like-member continuous bodies being welded together in the side-seal section, the cutting target positions being set at a predetermined pitch in the direction of transport; a cutting step of producing the absorbent article (1) that has the elastic member (35) and the first and second sheet-like members, the cutting step being performed by cutting at each of the cutting target positions. In the joining-portion forming step, the joining portions are formed on two sides of the elastic-member continuous bodies in the CD direction while maintaining the elastic-member continuous bodies being stretched in the direction of transport. After the cutting step, the elastic member is expanded in the CD-direction, and is sandwiched and pressed by the joining portions on the two sides. As viewed in the thickness direction, at least a part of the joining portions are overlapped with a portion of the side-seal section.